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USE OF KAPOK PULP TO IMPROVE PROPERTIES OF RECYCLED PAPER 246 The Journal of the Royal Institute of Thailand Vol. 37 No. 1 Jan.-Mar. 2012 to improve the tensile strength of recycle paper but the effects of kapok pulp is more pronounced than softwood pulp in terms of increasing tensile strength of papers. Tear index The effects of number of recycling cycles and pulp type on tear index are shown in Figure 7. Tear index was defined as tear resistance divided by grammage. It was clear that number of recycling did not produce effect on tear index. Paper made from only softwood fibers had a high - est tear index while the tear index of paper made from 100% kapok pulp was close to those from recycled pulp. The lowest tear index was found when 100% recycled fibers was used to make the paper. Adding the kapok fibers in the recycled pulp did not provide any benefit in terms of tear index improvement; however, tear index was slightly improved when softwood pulp was added to the recycled pulp. Conclusion Recycling seemed to have a small impact on paper properties. However, only up to three cycles of recycling were evaluated in this study. If the numbers of recycling Figure 7 The Effects of Recycling Cycles, Kapok Pulp and Softwood (SW) Pulp on Tear Index Note: Kapok and SW pulps have tear index values of 6.622 mN m/g and 53.037 mN m/g, respectively)